## Crowds: Anonymity for Web Transactions

### Authors: Michael K. Reiter and Aviel D. Rubin

ABSTRACT

In this announcement we introduce a system called Crowds for protecting users' anonymity on the world-wide-web. Crowds, named for the notion of blending into a crowd'', operates by grouping users into a large and geographically diverse group (crowd) that collectively issues requests on behalf of its members. Web servers are unable to learn the true source of a request because it is equally likely to have originated from any member of the crowd, and indeed collaborating crowd members cannot distinguish the originator of a request from a member who is merely forwarding the request on behalf of another. Our security analysis introduces {\em degrees of anonymity} as an important tool for describing and proving anonymity properties.

Paper Available at: ftp://dimacs.rutgers.edu/pub/dimacs/TechnicalReports/TechReports/1997/97-15new.ps.gz